Free Sauna designer and builder's plan
Any size, the right heater. Every board priced.
Set the inside size. The designer places the benches at the heights heater makers ask for, sizes the heater to the room, lays out the vents and prices every board, batt and screw from real store listings, free. When you are ready to build, the builder's plan for your exact sauna is $39: drawings, cut list, shopping list and the build in order.
- Inside 4 to 10 ft wide, 4 to 12 ft deep
- Electric 240 V or wood-fired, indoor or outdoor
- Checked against heater makers' data
- Every line priced, store and date shown
Where sauna builds go wrong
Six mistakes. The designer checks every one.
The heater is the wrong size
Too small and the room never gets hot. Makers rate every heater for a range of room volume, and glass counts extra: a glass door adds about 48 cu ft of load to a 6 x 7 ft room.
The planner checks
Heater sized to the room. The 6 x 7 ft room with a 7 ft ceiling is 294 cu ft, so it gets the Harvia 8 kW, rated 250 to 425 cu ft.
Source: Harvia, How do I select the correct heater power?, Haven of Heat, Heater listings with the maker's room ranges
The top bench sits too low
Heat pools under the ceiling. A bench set by eye leaves your head in the cooler air and your feet in the cold layer by the floor.
The planner checks
Top bench to ceiling, 43 to 51 in. The 6 x 7 ft puts the top bench 46 in below the 7 ft ceiling, with the lower tier at 20 in.
The room cannot breathe
A sealed box gets stuffy and stays damp. Fresh air has to come in low by the heater and leave low on the far wall, with a vent up high to dry the room after a session.
The planner checks
Ventilation. Intake about 8 in up beside the heater, exhaust at 24 in on the back wall, drying vent at 76 in: about six air changes an hour.
The vapor barrier is wrong
Plastic sheeting and open seams trap steam in the wall, and boards nailed tight to the foil never dry. That is how a sauna wall rots from the inside.
The planner checks
Wall build-up. Aluminum foil, shiny side in, every seam and hole taped, then 1x2 furring for an air gap before the boards. The foil, tape and furring are on the shopping list.
The heater is too close to the wood
Every heater and stove has a clearance to anything that burns. Miss it and the wall behind the heater chars over the years.
The planner checks
Clearances from the maker's data: 3/4 in in front, 1-3/8 in at the sides and 43-1/4 in to the ceiling for the Harvia KIP; 11.81 in front and back and 11.81 in at the sides for the Harvia M3 wood stove.
Source: Harvia, KIP45 product data, Harvia, M3 wood-burning heater product data
The bill keeps growing
Foil, tape, vents, door hardware, the circuit: the forgotten lines turn a weekend budget into second trips and a bigger card bill.
The planner checks
Every line priced. $8,481 for the 6 x 7 ft example over 47 lines, each with its store and date, plus 5 to price locally, the electrician included. The 8 kW heater draws 33.3 A at 240 V, so its conductors are sized for 41.7 A.
How it works
Three steps from room to lumber yard
Step 1
Size the room
Inside width, depth and ceiling, an indoor room or an outdoor cabin. The benches go on the back wall at the heights the heater maker asks for; the heater and the door share the front wall.
Step 2
Choose heat and wood
Electric 240 V or a wood stove, one or two tiers, straight or L bench, cedar or thermally modified boards, a built or glass door. The heater, the checks and the price follow every change.
Step 3
Build from the plan
Keep everything on screen for free, or get the builder's plan for $39: the drawings, the cut list, the shopping list and the build in order, for exactly the sauna you designed.
The builder's plan
Every board, every cut, every step. For your sauna.
Not a stock plan stretched to fit: the sheets are drawn from your design, so the studs, the boards, the heater and the shopping list match the sauna on your screen. One payment of $39, no subscription.
Cover and designSize, heater, benches, total
Plan and sectionBenches, heater and vents, dimensioned
Heater, power and airClearances, circuit, each vent, wall layers
Materials and pricesThe store and the date on every line
Cut listEvery part, its length and count
Build sequence12 steps, in order
Real sheets, 6 of 13, from the plan for the 6 x 7 ft outdoor sauna with an electric heater and two tiers. Tap a sheet to see it full size.
| What you get | Free | Plan, $39 |
|---|---|---|
| Any inside size from 4 to 10 ft wide and 4 to 12 ft deep, indoor or outdoor | Included | Included |
| Benches placed at the heights the heater maker asks for | Included | Included |
| Heater picked from the maker's room ranges, glass counted | Included | Included |
| Every check with the source behind it | Included | Included |
| Plan and section drawings | Included | Included |
| Materials list with store prices, dates and the total | Included | Included |
| Cut list | Included | Included |
| Each vent placed with its height, and the wall layer by layer | Not included | Included |
| Build sequence in 12 steps, in the order you build | Not included | Included |
| One printable PDF with tick boxes on the shopping and cut lists | Not included | Included |
| Plan error guarantee: we fix it or refund you | Not included | Included |
One-time payment
Builder's plan $39
- For the exact sauna you designed
- 13 sheets on Letter paper for the 6 x 7 ft example, one PDF
- Download right after payment, link by email
- Yours to keep: the plan does not expire
Our guarantee. If our plan has an error, we fix it or refund you. An error means the plan does not match the design you bought, or a number, drawing or calculation in it is wrong. Terms
You buy from the designer, once the design is the way you want it.
Plan, kit or builder
Three ways to get a sauna. Here is the honest math.
Build from our plan
$39 + materials
The 6 x 7 ft outdoor sauna above: $8,481 in materials and a Harvia 8 kW heater at store prices read Sep 30 to Oct 9, 2026, before freight, tax and the electrician.
- Any inside size from 4 x 4 ft to 10 x 12 ft
- Framed, insulated and foil-lined, the heater sized to the room
- You see every line and its price before you pay anything
- You build it; a licensed electrician wires the heater
Buy a cabin kit
$6,106 to $7,146
Two outdoor cabin kits at Haven of Heat on Oct 10, 2026: the Dundalk Granby (inside 5 x 5 ft) and the Palmer (inside 7 x 5 ft). The heater is sold separately; the Harvia KIP 6 kW the store suggests for the Granby lists at $1,254.
- Pre-cut, with benches and an installation guide
- Fixed sizes and layouts
- Heater sold separately
- You still assemble it, on a level base, with the electrician
Have one built
$12,000 to $34,000
HomeGuide's range for a custom-built outdoor sauna, installed (cost guide last updated Sep 5, 2023, read Oct 10, 2026).
- No building for you
- Their design, their schedule
- A wide range: get more than one quote
Listed prices as we read them on the day, before tax and delivery; they change. We have not priced labor. Every material figure on this site is the plan's own shopping list priced at a named store on a named date.
Proof, not promises
Every check shows where its number comes from
The rules come from heater makers' manuals and product data and from the National Electrical Code, each cited with the date we read it. Where a number is our own choice, the check says so. These are the checks on the 6 x 7 ft example, straight from the designer.
- Checks OK on the 6 x 7 ft, 3 notes
- 9/12
- Priced lines on its list
- 47
- Lines on its cut list
- 37
- Sources cited
- 8
| Check | This sauna | Rule | Source |
|---|---|---|---|
| Ceiling height | 7 ft | 79 to 91 in (2.0 to 2.3 m); never under the heater's minimum room height of 6.56 ft | HUUM |
| Top bench to ceiling | 46 in | 43 to 51 in (1100 to 1300 mm) | HUUM |
| Lower bench | top at 20 in | 18 in step below the top bench, 15 to 22 in off the floor (our default) | Our default |
| Seats on the top bench | 3 at 24 in each | About 24 in (60 cm) of bench per person | Harvia |
| Floor in front of the benches | 41 in | 30 in or more to stand and reach the benches (our default); under 24 in fails | Our default |
| Room for the heater and its clearances | 41 in | 23-3/4 in: 3/4 in front and 1-3/8 in side per Harvia's KIP data; confirm in your model's manual, the heater, and 12 in to pass | Harvia |
| Heater wall fits the door and the heater | 72 in | 67-1/2 in: heater with its guard and side clearances, 12 in to pass, door rough opening and trim | Harvia |
| Heater to ceiling | 54 in | 43-1/4 in or more from the heater top to the ceiling (maker's data; heater top taken at about 30 in) | Harvia |
| Heater sized to the room | 294 cu ft, Harvia 8 kW for 250 to 425 | Room volume, plus 1.2 m3 for every m2 of glass, inside the heater's rated range; we pick the next size up past 90 percent of a range (our default) | Harvia |
| Ventilation | Intake low by the heater, exhaust low on the opposite wall, drying vent high | Supply 2 to 4 in, exhaust twice that, about six air changes an hour | HUUM |
| Electrical circuit | 33.3 A at 240 V; conductors for at least 41.7 A | 125 percent of the heater load; breaker and wire per the heater's manual, installed by a licensed electrician | NFPA 70, National Electrical Code |
| Door | Built cedar door, opens out | Opens outward, no lock or latch that holds it shut | Our default |
Sources
What the planner reads, and when we read it
HUUM
DROP 2.0 electric heater user manual (EU, v6)Room 2000 to 2300 mm high, never under 1900 mm; top bench 1100 to 1300 mm below the ceiling; 50 to 100 mm insulation, foil with taped joints, 10 mm gap behind the boards, 12 to 16 mm boards, 100 mm from the floor; supply air 50 to 100 mm at or below heater mid-height (400 mm), exhaust twice that on the opposite wall at least 200 mm higher (600 mm), drying vent under the ceiling; six air changes an hour; only a certified electrician connects the heater.
Read 2026-10-09
Harvia
How do I select the correct heater power?Each square meter of stone, glass or similar uninsulated surface adds as much load as 1.2 cubic meters of room volume.
Read 2026-10-09 (search listing; the page answered 403)
Harvia
KIP45 product dataRoom 106 to 212 cu ft, minimum room height 6.56 ft, 3.61 ft from the heater to the ceiling.
Read 2026-10-09
Harvia
M3 wood-burning heater product dataRoom 212 to 459 cu ft; to combustible material 11.81 in front and rear, 9.84 in each side; minimum room height 6.56 ft.
Read 2026-10-09
Harvia
Pro 20 wood-burning heater product data300 mm (11.81 in) to combustible material front, rear and sides; 1.3 m to the ceiling; minimum room height 2 m.
Read 2026-10-09 (search listing)
Harvia
How to design a saunaThe seat for one person is usually 60 cm wide.
Read 2026-10-09
Haven of Heat
Heater listings with the maker's room rangesHarvia KIP 4.5 kW 100 to 210 cu ft, 6 kW 170 to 300, 8 kW 250 to 425; Cilindro 9 kW 141 to 494; Harvia M3 212 to 459; Pro 20 283 to 706.
Read 2026-10-09
NFPA 70, National Electrical Code
Article 424.4(B), branch-circuit sizing for fixed electric space-heating equipment (2020 text)Branch-circuit conductors are sized at no less than 125 percent of the load. Your jurisdiction's adopted edition and the heater's nameplate govern.
Read 2026-10-09 (secondary summary)
Store prices are read separately, line by line: each line on the materials list names its store and the day we read it. The heater or stove manual for your exact model always wins over the planner.
Read before you build
DIY sauna
What it takes, what it costs, and where DIY saunas go wrong.
Read the guideHow to build a sauna
The build step by step, from footing to first heat.
Read the guideSauna plans
Fixed plans versus a plan made for your room, with priced examples.
Read the guideOutdoor sauna
Footing, roof, wiring and what an outdoor build costs.
Read the guideBefore you buy
What exactly do I get for $39?
One PDF for the sauna you designed, on Letter paper: 13 sheets for the 6 x 7 ft outdoor example. The cover with your design, every check with its source, the plan and section, a heater, power and air sheet with each vent and the wall build-up, the materials list with the store and the date on each line, the cut list, the build sequence in 12 steps and the sources.
Is the designer really free?
Yes. The sizing, the bench layout, the heater pick, the checks, the drawings, the priced materials list and the cut list are free on screen, with no sign-up. You pay only if you want the builder's plan for your design as one printable PDF.
How do I receive the plan?
Right after payment you go to a download page, and we email you a receipt with a link to your plan. The plan does not expire: if you lose it, Get my plan emails a fresh link, good for 48 hours, to the address you paid with.
What if the plan has a mistake?
Email us from the address you paid with. If the plan does not match the design you bought, or a number, drawing or calculation in it is wrong, we fix it or refund you. The details are in our terms.
Is it cheaper to buy or build a sauna?
For a small sauna a kit is cheaper up front; building gets you the size you want. The 6 x 7 ft outdoor sauna on this page comes to $8,481 in materials and heater at the store prices we read. Two outdoor cabin kits with smaller rooms listed at $6,106 and $7,146 at Haven of Heat on Oct 10, 2026, heater sold separately. HomeGuide puts a custom-built outdoor sauna at $12,000 to $34,000 installed.
How big should my sauna heater be?
Work out the room volume, add load for glass and bare stone, and pick a heater whose maker-rated range covers it. The 6 x 7 ft room with a 7 ft ceiling is 294 cu ft: a Harvia 8 kW, rated 250 to 425 cu ft. A glass door adds about 48 cu ft. Past 90 percent of a heater's range, the designer picks the next size up.
Do you need a 220 line for a sauna?
For an electric heater, yes: heaters this size run on 240 V, often called 220. The 8 kW heater here draws 33.3 A, so its circuit conductors are sized for at least 41.7 A (125 percent, NEC 424.4(B)), installed by a licensed electrician. A wood stove needs no heater circuit.
Is building your own sauna hard?
It is basic carpentry: framing, insulation, foil, boards and benches. The planner does the numbers and the order of work. The 240 V circuit is a job for a licensed electrician, and a wood stove's chimney goes in exactly as its manual says.
Do you need a permit for a backyard sauna?
Often. A new 240 V circuit usually needs an electrical permit, and many towns want a building permit for an accessory building over a size limit or with a wood stove. The planner cannot see your site or your local rules: check with your building department before you buy lumber.
Your sauna, sized and priced
Design the sauna free. Buy the plan only when you are ready to build.
A planning aid, not an approval. A sauna heater is a 240 V appliance and a wood stove is a fire inside a wooden room: install either exactly as its manual says, have a licensed electrician connect an electric heater, and get the permits your town requires.